The present invention relates to a pedal system capable of electrically controlling a pedal travel or a pedal reaction force or a vehicle output, and a vehicle provided with the pedal system.
Conventionally, a driving force and a braking force of a vehicle are operatively manipulated by a pedal. Stepping on a pedal, a driver physically feels an inertial force generated by acceleration and deceleration of a vehicle as well as a pedal reaction force. Therefore, properties such as a pedal travel, a pedal reaction force, a driving force and a braking force of a vehicle, etc. constitute factors that determine a feeling of driving, easiness of operation, susceptibility to fatigue, etc.
On the other hand, since a conventional pedal is mechanically connected to an accelerator wire and a master cylinder, characteristics of the pedal is uniquely determined by the mechanism.
In recent years, however, a technique, so-called bi-wire, makes it possible to arbitrarily set the relationship among a pedal travel, or a pedal reaction force, or a driving force and a braking force of a vehicle, and examination has been repeated on how the relationship among the pedal travel, or the pedal reaction force, or the driving force and the braking force of the vehicle should be controlled.
There is known a technique that varies pedal travel characteristics, braking force characteristics, and pedal effort characteristics according to, for example, an operating direction of a braking force and an operating direction of a brake pedal. (See JP-A-11-291894)
In a pedal system capable of arbitrarily setting a pedal travel and a pedal reaction force, an operating direction of a pedal is determined on the basis of balance of stepping by a driver with a force, which is generated by the pedal system. That is, there is caused a problem that since an operating direction of a pedal is resulted from control on the pedal system, delay occurs in reaction of the pedal relative to a pedal manipulation by a driver if the pedal system is controlled on the basis of the operating direction of the pedal, and stepping and releasing motions intended by the driver does not necessarily correspond to an actual operating direction, thus bringing about a sense of incongruity.
Reference is made in the conventional technique to the case where a driver performs a stepping motion and the case where a driver performs a releasing motion. However, there is caused a problem that consideration is not adequately given to a holding motion in the case where stepping on a pedal is maintained constant.